This invention relates generally to internal combustion engine fuel injection systems and in particular to fuel injection systems utilizing spill valves to control the quantity and timing of injection of fuel.
In some fuel injection systems of the prior art two valves are used, one to initiate fuel injection and the other to terminate fuel injection. Such configurations were required because of the inertia of the valve elements and the high operating speeds of the valves, of the order of 10.sup.-3 seconds. The valve used for initiating the start of injection is generally fuel pressure operated.
Another fuel injection system utilizes a solenoid operated spill valve to control fuel flow to a fuel injection nozzle, however, without disclosing any method of relating control of the valve to engine operating parameters.
Other fuel injection systems utilize solenoid operated fuel pump/injectors only.
Still other injection systems utilize variable volume fuel injection pumps to control the amount of fuel injected into the internal combustion engine.